/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.coyote.http11.upgrade;

import org.apache.tomcat.util.net.NioChannel;
import org.apache.tomcat.util.net.NioEndpoint;
import org.apache.tomcat.util.net.NioSelectorPool;
import org.apache.tomcat.util.net.SocketWrapper;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.Selector;

/**
 * @deprecated Will be removed in Tomcat 8.0.x.
 */
@Deprecated
public class UpgradeNioProcessor extends UpgradeProcessor<NioChannel> {

	private final NioChannel nioChannel;
	private final NioSelectorPool pool;
	private final int maxRead;
	private final int maxWrite;

	public UpgradeNioProcessor(SocketWrapper<NioChannel> wrapper,
	                           UpgradeInbound upgradeInbound, NioSelectorPool pool) {
		super(upgradeInbound);

		wrapper.setTimeout(upgradeInbound.getReadTimeout());

		this.nioChannel = wrapper.getSocket();
		this.pool = pool;
		this.maxRead = nioChannel.getBufHandler().getReadBuffer().capacity();
		this.maxWrite = nioChannel.getBufHandler().getWriteBuffer().capacity();
	}

	/*
	 * Output methods
	 */
	@Override
	public void flush() throws IOException {
		NioEndpoint.KeyAttachment att =
				(NioEndpoint.KeyAttachment) nioChannel.getAttachment();
		if (att == null) {
			throw new IOException("Key must be cancelled");
		}
		long writeTimeout = att.getTimeout();
		Selector selector = null;
		try {
			selector = pool.get();
		} catch (IOException x) {
			//ignore
		}
		try {
			do {
				if (nioChannel.flush(true, selector, writeTimeout)) {
					break;
				}
			} while (true);
		} finally {
			if (selector != null) {
				pool.put(selector);
			}
		}
	}

	@Override
	public void write(int b) throws IOException {
		writeToSocket(new byte[]{(byte) b}, 0, 1);
	}

	@Override
	public void write(byte[] b, int off, int len) throws IOException {
		int written = 0;
		while (len - written > maxWrite) {
			written += writeToSocket(b, off + written, maxWrite);
		}
		writeToSocket(b, off + written, len - written);
	}

	/*
	 * Input methods
	 */
	@Override
	public int read() throws IOException {
		byte[] bytes = new byte[1];
		int result = readSocket(true, bytes, 0, 1);
		if (result == -1) {
			return -1;
		} else {
			return bytes[0] & 0xFF;
		}
	}

	@Override
	public int read(boolean block, byte[] bytes, int off, int len)
			throws IOException {
		if (len > maxRead) {
			return readSocket(block, bytes, off, maxRead);
		} else {
			return readSocket(block, bytes, off, len);
		}
	}

	/*
	 * Adapted from the NioInputBuffer.
	 */
	private int readSocket(boolean block, byte[] bytes, int offset, int len)
			throws IOException {

		ByteBuffer readBuffer = nioChannel.getBufHandler().getReadBuffer();
		int remaining = readBuffer.remaining();

		// Is there enough data in the read buffer to satisfy this request?
		if (remaining >= len) {
			readBuffer.get(bytes, offset, len);
			return len;
		}

		// Copy what data there is in the read buffer to the byte array
		int leftToWrite = len;
		int newOffset = offset;
		if (remaining > 0) {
			readBuffer.get(bytes, offset, remaining);
			leftToWrite -= remaining;
			newOffset += remaining;
		}

		// Fill the read buffer as best we can
		readBuffer.clear();
		int nRead = fillReadBuffer(block);

		// Full as much of the remaining byte array as possible with the data
		// that was just read
		if (nRead > 0) {
			readBuffer.flip();
			readBuffer.limit(nRead);
			if (nRead > leftToWrite) {
				readBuffer.get(bytes, newOffset, leftToWrite);
				leftToWrite = 0;
			} else {
				readBuffer.get(bytes, newOffset, nRead);
				leftToWrite -= nRead;
			}
		} else if (nRead == 0) {
			readBuffer.flip();
			readBuffer.limit(nRead);
		} else if (nRead == -1) {
			throw new EOFException(sm.getString("nio.eof.error"));
		}

		return len - leftToWrite;
	}

	private int fillReadBuffer(boolean block) throws IOException {
		int nRead;
		if (block) {
			Selector selector = null;
			try {
				selector = pool.get();
			} catch (IOException x) {
				// Ignore
			}
			try {
				NioEndpoint.KeyAttachment att =
						(NioEndpoint.KeyAttachment) nioChannel.getAttachment();
				if (att == null) {
					throw new IOException("Key must be cancelled.");
				}
				nRead = pool.read(nioChannel.getBufHandler().getReadBuffer(),
						nioChannel, selector, att.getTimeout());
			} catch (EOFException eof) {
				nRead = -1;
			} finally {
				if (selector != null) {
					pool.put(selector);
				}
			}
		} else {
			nRead = nioChannel.read(nioChannel.getBufHandler().getReadBuffer());
		}
		return nRead;
	}

	/*
	 * Adapted from the NioOutputBuffer
	 */
	private synchronized int writeToSocket(byte[] bytes, int off, int len)
			throws IOException {

		nioChannel.getBufHandler().getWriteBuffer().clear();
		nioChannel.getBufHandler().getWriteBuffer().put(bytes, off, len);
		nioChannel.getBufHandler().getWriteBuffer().flip();

		int written = 0;
		NioEndpoint.KeyAttachment att =
				(NioEndpoint.KeyAttachment) nioChannel.getAttachment();
		if (att == null) {
			throw new IOException("Key must be cancelled");
		}
		long writeTimeout = att.getTimeout();
		Selector selector = null;
		try {
			selector = pool.get();
		} catch (IOException x) {
			//ignore
		}
		try {
			written = pool.write(nioChannel.getBufHandler().getWriteBuffer(),
					nioChannel, selector, writeTimeout, true);
		} finally {
			if (selector != null) {
				pool.put(selector);
			}
		}
		return written;
	}
}
